TRACHE.E. 



[ 648 ] 



TREBIUS. 



with dilatations forming air-sacs, in which 

 the spiral fibre is absent. 



An unsettled point in regard to the tra- 

 cheae is the presence of a peritracheal circu- 

 lation. When larvae are fed with indigo or 

 carmine, or when the dorsal vessel is injected 

 with colouring matter, the tracheae become 

 coloured, which some authors believe to 

 arise from the nutritive liquid circulating 

 between the membranes of the tracheae; 

 whilst by others this circulation, or the ex- 

 istence of a space bet ween the tracheal mem- 

 branes, is denied. 



BIBL. That of INSECTS ; Newport, Phil. 

 Trans. 1836. 529; Platner, Miiller's Archiv, 

 1844. xxxviii. ; Stein, Vergleich. Anat. d. 

 Insekten ; Agassi/, Ann. des Sc. not. 3 ser. 

 xv.; Bassy, ibid.; Joly, ibid. xii. ; Blanchard, 

 Comptes Rendus, 1851, or Ann. Nat. Hist. 

 1852. ix. 74 ; Dufour, Comptes Rendus, 1851 , 

 or Ann. Nat. Hist. 1852. ix. 435; Meyer, 

 Siebold and Kolliker's Zeitsch. i. 1 75. 



TRACHEAE, OF PLANTS. This name 

 was formerly applied to the unreliable SPI- 

 RAL VESSELS of Plants, from their resem- 

 blance to the tracheae of Insects. 



TRACHELINA, Ehr. A family of Infu- 

 soria. 



Char. Carapace absent ; alimentary canal 

 with two distinct orifices, the anal only ter- 

 minal. 



Locomotive organs consisting of cilia co- 

 vering the body in longitudinal rows, but 

 absent in Phialina ; those around the mouth 

 longer. In two genera teeth are present. 

 Mouth situated on the under surface of the 

 body. 



Eight genera : Bursaria, Chilodon, Glau- 

 coma, Loxodes, Nassula, Phialina, Spiro- 

 stoma, Trachelius. 



BIBL. Ehrenberg, In/us. 319. 



TRACHELIUS, Schrank, Ehr. A genus 

 of Infusoria, of the family Trachelina. 



Char. Body covered with cilia; mouth 

 not spiral, without teeth; upper lip much 

 elongated in the form of a proboscis. 



In three species the cilia have not been 

 detected ! 



T. lamella (PI. 25. fig. 5). Body depressed, 

 lamellar, linear -lanceolate, often truncate in 

 front, rounded behind. Aquatic; length 

 1-430 to 1-290". 



Eight other species (Ehr.). Dujardin 

 places some of the species in the genera 

 Loxophyllupn and Amphileptus, and adds 

 three new ones. 



BIBL. Ehrenberg, In/us. 320, and Ber. d. 

 Berl. Akad. 1840. 202 ; Dujardin, In/us. 398. 



TRACHELOCERCA, Ehr. A genus of 

 Infusoria, of the family Ophryocercina. 



Char. Those of the family (= caudate 

 Lachrymarice}. 



Four species. 



T. olor (Lachrymaria olor, D.). Body 

 fusifornijwhite ; neck very long, simple, very 

 moveable, and the dilated end containing 

 the ciliated mouth. Aquatic; length 1-36". 



T. mridis (PI. 24. fig. 33). Body green; 

 neck as in the last. Aquatic; length 1-120". 



T. biceps. Neck bifid at the end. 



BIBL. Ehrenberg, Infus. 341, and Ber. d. 

 Berl. Akad. 1840. 202. 



TRACHELOMONAS, Ehr. A genus of 

 Infusoria, of the family Cryptomonadina. 



Char. Body enclosed in a spherical or 

 ovoid hard and brittle envelope, having a 

 small aperture, from which a long flagelliform 

 filament projects, but no neck (?) ; eye-spot 

 present. 



T. volvocina (PI. 23. fig. 24 d, empty en- 

 velope). Spherical, green, brownish, or red ; 

 eye-spot red. Aquatic; length 1-865". 



T. nigricans. Ovate -globose, green, black- 

 ish-brown or reddish; eye-spot brownish. 

 Aquatic; length 1-1730". 



T. cylindrica. Oblong - subcylindrical ; 

 bright green; eye-spot red. Aquatic; length 

 1-1000". 



The bodies represented in PI. 23. fig. 24 

 (btog} } and which are commonly found in 

 bog-water, probably belong here, with the 

 genera Chatoglena (a), Ch(Etotyphla (fig. 26), 

 and Doxococcus (fig. 47). The margins of 

 the red envelope appear as a bright red ring, 

 on account of the greater thickness traversed 

 by the light. They are probably spores of 

 Algae. 



BIBL. Ehrenberg, Infus. 47. 



TRADESCANTIA, L. A genus of Com- 

 melynaceae ( Monocotyledons ), commonly 

 cultivated in gardens under the name of 

 * Spider-worts/ These plants are celebrated 

 for having served as material for some of the 

 most remarkable observations on the physio- 

 logical processes of vegetables, as the ROTA- 

 TION of the cell-contents, and the multipli- 

 cation of the cells, so well seen in the hairs 

 of the stamens when young (PI. 36. figs. 8 & 

 9). The stems, petioles, &c. afford beautiful 

 spiral, annular, and reticulated vessels, &c. 



TREBIUS, Kroyer. A genus of Crusta- 

 cea, of the order Siphonostoma, and family 

 Caligidae. 



Char. Head in the form of a large buckler, 

 with the large frontal plates destitute of 

 sucking disks ; thorax three-jointed, seg- 



